METABOLISM – Notes
Use of stored energy to do work in the body
Anabolic > synthesis/storage of chemical fuels, requires energy, occurs in all body cells that
divide to form new ones, maintains intracellular structure, produces molecules (hormones,
neurotransmitters) for export.
Catabolic > Breakdown of fuel with release of energy, begins in digestion, concludes in
individual cells, energy is used to drive anabolic reactions, active transport, muscle contractions
Glycogen > multiple glucose stuck together by chemical bonds
In plants, dairy products (lactose)
Monosaccharides, disaccharides, polysaccharides
Monosaccharides > include glucose and fructose. Plants produce glucose by sunlight energy (in
Fructose + galactose > isomers of glucose, fructose is in fruits, berries, corn syrup. Galactose is
Sucrose > dissacharide, glucose+fructose combined, in sugarcane, maple sugar, etc.
Maltose > derived from germinating cereals (2 glucose and lactose) consists of glucose and
Complex Carbs > polysaccharides, starch, glycogen, cellulose. Starch (energy storage molecules
found in plants), Glycogen (energy storage molecule in animals, muscle and liver). Processed
meats have little to no glycogen left because it is used by dying muscle cells. Cellulose (forms
plant cell walls).
Poly / Di saccharides broken into monosaccharides in digestion, absorbed by blood. Humans
produce enzymes that break bonds between glucose molecules of starch/glycogen. Do NOT
produce enzymes that break bonds between cellulose glucose molecules. Cellulose provides
fiber (roughage) increasing bulk of feces/easier for defecation.
Liver > converts fructose, galactose, other monosaccharides absorbed by blood into glucose*.
Glucose provides energy to produce ATP. Muscle/Liver cells convert excess glucose to glycogen. Cells only hold certain amt of glycogen,
the rest of glucose is converted to lipids/stored in adipose tissue. Glycogen can be converted
back to glucose (exercise, between meals).
Sugars make DNA, RNA, combine to form glycoproteins (glycoprotein receptor molecules on
surface of plasma membranes).
95% triglycerides * > 3 fatty acids attached to glycerol molecule.
Fats > solid at room temp
Oils > liquid at room temp
Saturated fats/oils > single covalent bonds between carbon atoms of fatty acids (meat fats,
dairy products, eggs, coconut oil, etc.)
Unsaturated fats/oils > one or more double covalent bonds between carbon atoms of fatty
Monosaturated fats > one double bond (olive/peanut oil)
Polyunsaturated fats > 2 or more double bonds (fish, sunflower, corn oil)
Unsaturated > classified based on location of first double bond on omega end of fatty acid
(omega-3 = first double bond starts 3 carbons after omega end, etc.)
5% lipids > cholesterol/phospholipids (lecithin)
Cholesterol > steroid in high concentrations in egg yolks/liver, not in plants
Phospholipids > major components of plasma membranes, also in egg yolks
Cis > bends, hard for multiple molecules to lineup/form a sheet
Trans > straight, line up and form precipitate, hydrogen are in opposite directions
Chains of amino acids, 20 kinds of amino acids > essential and non essential
Essential amino acids > body cannot synthesize, obtained in diet *
Nonessential > necessary to construct proteins, can be synthesized from essential amino acids Complete Protein > food that contains all 9 essential amino acids (meat, milk, cheese, eggs)
Incomplete Protein > does not (leafy vegetables, grains)
2 incompletes are ingested > 2 amino acids complement, form complete proteins.
Essential/nonessential amino acids synthesize proteins. Collagen > provides structural strength
in CT, Ketarin > in skin
Emzymes > regulate rate of chemical reactions
Protein hormones > regulate physiological processes
Proteins in blood > prevent pH changes (buffers), transport O2 and CO2 (hemoglobin)
Transport proteins > move materials across plasma membrane, also function as receptor
Antibodies, lymphokines, complement, part of immune system response that protects against
Proteins > used for energy, excess convert amino acids to glycogen or lipids.
Organic molecules essential to normal metabolism, nucleic acid synthesis, blood clotting
Essential vitamins > obtained through diet, not made by body (no food provides ALL essential
Vitamin K > by intestinal bacteria, others formed by body to form povitamins *
Provitamins > part of vitamin that body can assemble/modify into functional vitamin (beta
carotene into vitamin A)
Coenzymes > combine with enzymes to make enzymes functional, without them reactions
would occur too slowly for good health.
Fat soluble or water soluble *
Fat soluble > A, D, E, K dissolve in lipids, absorbed from intestine with lipids, can be stored for a
long time, if too long can cause toxicity of the body.
Water soluble > B vitamins/ C, dissolve in water, absorbed from water in intestinal tract, remain
in body for short period, excreted in urine. Minerals
Inorganic nutrients, necessary for metabolic functions, 2 groups:
Major minerals > 100mg or more daily required
Trace minerals > less than 100mg a day will work
4-5% body weight, components of coenzymes, some vitamins, hemoglobin, organic molecules.
Establish resting membrane potential, generate AP’s, add mechanical strength to bones/teeth,
combine w/ organic materials, act as coenzymes, buffers, regulate osmotic pressure.
Animal/plant sources, limited in plants bc minerals bind to plant fibers.
Chemical reactions responsible for transferring energy from chemical bonds of nutrient
molecules to ATP involve oxidative/reduction reactions *
Molecule is reduced > when it gains electrons
Molecule is oxidized > when it loses electrons
Nutrient molecule has H atoms covalently bonded to carbon atoms to make a backbone of a
molecule. H+ atom has H and an electron, nutrient molecule has many electrons and is highly
reduced. When H+ atom and electron are lost from nutrient molecule, molecule loses energy
and becomes oxidized, energy in the electron synthesizes ATP.
In Oxidation, electrons are moved by 2 intermediate carriers
NAD+ (niacin) + 2H NADH + H+
FAD (flavin adenine dinucleotide) + 2H FADH2